* {
    margin: 0;
    padding: 0;
}

body {
    background-color: #f3f5f7;
    height: 3000px;
}

/*通用*/
a {
    text-decoration: none;
}

/*清除浮动常用固定代码，注意要给被清除浮动的标签命名为clearfix*/
.clearfix:before,
.clearfix:after {
    content: "";
    display: table;
}

.clearfix:after {
    clear: both;
}

.clearfix {
    *zoom: 1;
}

/*通用版心，特别好用！*/
.w {
    width: 1200px;
    margin: auto;
}

ul li {
    list-style: none;
}

.nav ul li {

    float: left;
    list-style: none;
    height: 42px;
    padding: 0 10px;
    margin: 0 15px;
}

.nav ul li a {
    display: block;
    height: 42px;
    padding: 0 10px;
    line-height: 42px;
    font-size: 18px;
    color: #050505;

}

.nav ul li a:hover {
    border-bottom: 2px solid #00a4ff;
    color: #00a4ff;
}

.header {
    height: 42px;
    background-color: white;
    margin: 30px, auto;

}

.logo {
    float: left;
    width: 198px;
    height: 42px;
    background-image: url(../images/logo_03.png);

}

.nav {
    float: left;
    margin-left: 60px;
}

.search {
    float: left;
    width: 412px;
    height: 42px;
    background-color: #00a4ff;
    margin-left: 50px;
}

.search input {
    float: left;
    width: 345px;
    height: 40px;
    border: 1px solid #00a4ff;
    border-right: 0;
    color: #bfbfbf;
    font-size: 14px;
    padding-left: 15px;
}

.search button {
    float: left;
    width: 50px;
    height: 42px;
    background-color: blue;
    border: 0;
    background-image: url(../images/btn.png);
}

.user {
    float: right;
    line-height: 42px;
    margin-right: 30px;
    font-size: 14px;
    background: color #666;
    ;
}

.banner {
    height: 421px;
    background-color: #1c036c;
}

.banner .w {
    height: 421px;
    background: url(../images/banner2.png) no-repeat top center;
}

/*左侧盒子*/
.subnav {
    float: left;
    width: 190px;
    height: 421px;
    background-color: rgba(0, 0, 0, .3);
}

.subnav li {
    height: 45px;
    line-height: 45px;
    padding: 10px;
}

.subnav ul li a {
    font-size: 14px;
    color: #fff;
}

.subnav ul li a span {
    float: right;
}

.subnav ul li a:hover {
    color: blue;
}

/*右侧盒子*/
.course {
    float: right;
    width: 230px;
    height: 300px;
    background-color: white;
    /*浮动的盒子不会有外边距合并问题*/
    margin-top: 50px;
}

.course h2 {
    height: 48px;
    background-color: #00a4ff;
    text-align: center;
    line-height: 48px;
    color: #fff;
    font-size: 18px;
}

.bd {
    padding: 0 20px;
}

.bd ul li {
    padding: 15px 0;
    border-bottom: solid#a5a5a5;

}

.bd ul li h4 {
    font-size: 16px;
    color: #4e4e4e;
}

.bd ul li p {
    font-size: 14px;
    color: #a5a5a5;
}

.bd .more {
    display: block;
    height: 37px;
    border: 1px solid #00a4ff;
    text-align: center;
    line-height: 37px;
    color: black;
    font-size: 16px;
    font-weight: 700;
    margin-top: 1px;
}

.goods {
    height: 60px;
    background-color: #fff;
    /*注意这里有阴影*/
    box-shadow: 0 2px 4px 3px rgba(0, 0, 0, .1);
    margin-top: 10px;
    /*行高会继承给 h3 , ul , mod*/
    line-height: 60px;
}

.goods h3 {
    float: left;
    margin-left: 30px;
    font-size: 16px;
    color: #00a4ff;
}

.goods ul {
    float: left;
    margin-left: 30px;
}

.goods ul li {
    float: left;
}

.goods ul li a {
    padding: 0 30px;
    font-size: 16px;
    color: #050505;
    /*巧妙的增加了竖线*/
    border-left: solid #ccc;
}

.mod {
    float: right;
    margin-right: 30px;
    font-size: 14px;
    color: #00a4ff;
}

.box {
    margin-top: 30px;
}

.box-hd {
    height: 45px;
}

/*要莫给box-hd一个高，要莫清除浮动，否则会使得下面的盒子顶上去*/
.box-hd h3 {
    float: left;
    font-size: 20px;
    color: #494949;
}

.box-hd a {
    float: right;
    font-size: 12px;
    color: #a5a5a5;
    /*浮动的元素不用担心外边距合并问题*/
    margin-top: 19px;
    margin-right: 30px;
}

/*把 ul 的父亲修改的足够宽，使得一行能够装下5个盒子，就不会出现换行的问题*/
.box-bd ul {
    width: 1225px;
}

.box-bd ul li {
    float: left;
    width: 228px;
    height: 270px;
    background-color: #fff;
    margin-right: 15px;
    margin-bottom: 15px;
}

.box-bd ul li img {
    width: 100%;
}

.box-bd ul li h4 {
    margin: 20px 20px 20px 25px;
    font-size: 14px;
    color: #050505;
    font-weight: 400;
}

.box-bd .info {
    margin: 0 20px 0 25px;
    font-size: 12px;
    color: #999;
}

.box-bd .info span {
    color: #ff7c2d;
}

/*小心上面的box模块的浮动对footer的影响*/
.footer {
    height: 415px;
    background-color: pink;
    width: 100%;
}

/*要避免外边距合并问题,所以此处选择使用padding*/
.footer .w {
    padding-top: 35px;
}

/*浮动的盒子自动检测宽度*/
.copyright {
    float: left;
}

.links {
    float: right;
}

.copyright p {
    font-size: 12px;
    color: #666;
    margin-top: 20px;
    margin-bottom: 15px;
}

.copyright .learnme {
    display: block;
    width: 250px;
    height: 50px;
    border: 2px solid red;
    border-radius: 10px;
    font-size: 18px;
    /*文字水平居中*/
    text-align: center;
    font-weight: 800;
    /*文字垂直居中*/
    line-height: 50px;
    color: #ff7c2d;
}

.links dl {
    float: left;
}

.links dl dt {
    font-size: 16px;
    color: black;
    margin-bottom: 10px;
}

.links dl dd a {
    font-size: 12px;
    color: black;
}